JS Operation select dropdown box dynamic change (Create/delete/get) _javascript tips

1. Create a Select dynamically

Copy Code code as follows:

function Createselect () {
var myselect = document.createelement_x ("select");
Myselect.id = "Myselect";
Document.body.appendChild (Myselect);
}

2. Add Options option

Copy Code code as follows:

function AddOption () {
To find an object based on its ID,
var obj=document.getelementbyidx_x (' Myselect ');
Add an option
Obj.add (New Option ("text", "value");
}

3. Delete all options option

Copy Code code as follows:

function RemoveAll () {
var obj=document.getelementbyidx_x (' Myselect ');
obj.options.length=0;
}

4. Delete an option

Copy Code code as follows:

function Removeone () {
var obj=document.getelementbyidx_x (' Myselect ');
Index, to delete the ordinal number of the option, take the number of the currently selected option
var Index=obj.selectedindex;
Obj.options.remove (index);
}

5. Get the value of options option

Copy Code code as follows:

var obj=document.getelementbyidx_x (' Myselect ');
var Index=obj.selectedindex; Ordinal number, taking the number of the currently selected option
var val = obj.options[index].value;

6. Get Options Option text

Copy Code code as follows:

var obj=document.getelementbyidx_x (' Myselect ');
var Index=obj.selectedindex; Ordinal number, taking the number of the currently selected option
var val = obj.options[index].text;

7. Modify Options option

Copy Code code as follows:

var obj=document.getelementbyidx_x (' Myselect ');
var Index=obj.selectedindex; Ordinal number, taking the number of the currently selected option
var val = obj.options[index]=new Option ("New text", "New value");

8. Delete Select

Copy Code code as follows:

function Removeselect () {
var myselect = document.getelementbyidx_x ("Myselect");
MySelect.parentNode.removeChild (Myselect);
}